Storage apparatus and control method thereof

ABSTRACT

Improvement of read/write access performance with respect to a disk is proposed. A controller manages a first volume format LDEV, in which each distributed user data area and each distributed information area among a plurality of the distributed user data areas for storing a data part and a plurality of the distributed control information area for storing a control information part, are targets that capacity is changed. The controller also manages a second format LDEV, which include a plurality of groups each of which is formed from one distributed user data area and one distributed control information area, and in which each group is a unit that capacity is expanded in a real storage area. The controller converts a data address of the data part belonging to the first volume format LDEV into a data address of a data part of the second volume format LDEV in order to execute input/output processing with respect to the data part, when received an request for access to the data part belonging to the first volume format LDEV.

TECHNICAL FIELD

The present invention relates to a storage apparatus and control methodfor managing the data placement in volumes configured from storagedevices.

BACKGROUND ART

Storage subsystems or storage apparatuses that employ disk drives etc.,as the storage devices are known. When data input/output processingagainst the storage devices is controlled the disk head is aligned.

For example, according to PTL1, a volume configured of storage devicesincludes one or more tracks. In a real storage area of the storagedevice there are a control information part in a top of the track (homeaddress, record 0) and a data part (record 1, record 2, . . . ) behindthe control information part. If a mainframe (MF) host computer issues arequest to a storage controller to read or write a track, the storagecontroller reads the track from the disk in accordance with a readcommand or write command, reads the value of the track controlinformation part (home address), confirms the track positioninformation, and executes read or write access to the data part afterconfirming that a head alignment has correctly been completed againstthe track.

CITATION LIST Patent Literature

-   PTL 1: U.S. Pat. No. 5,506,979

SUMMARY OF INVENTION Technical Problem

With the vigorous growth in online commercial transactions in recentyears, performance improvements are desirable in read or write access tostorage apparatuses connected to networks. Under this environment, theaforementioned storage controller expedites read access or write accessprocessing by omitting the processing to confirm the track positioninformation, and reading and writing only the data part from and todisks.

For example, when received a read access or write access request withrespect to a track from the host computer, the storage controllerdispenses with processing to confirm that processing to align the diskhead at the track header has been correctly performed without referringto the control information value in the track, the transfer of a controlinformation part to the storage controller from the disk is unnecessary,thereby enabling faster read access or write access processing.

However, the adoption of volume data placement, as disclosed in PTL1,involves a processing overhead for the storage controller, even thoughonly a data part is to be read from the disk, in causing the disk headto skip the position of the control information part in the track headerand positioning the head at the data part.

An object of the present invention is to provide a storage apparatus andcontrol method thereof enabling to improve read/write access performancewith respect to a disk.

Solution to Problem

In order to achieve the aforementioned object, the present inventioncomprising a controller which manages one or more logical volumesconstructed in storage areas of the storage devices, wherein thecontroller manages volumes, which can be recognized by an access requestsource, as first logical volumes, and which comprise a storage area witha first data placement in which a plurality of first data areas wheredata parts are placed and a plurality of first control information areaswhere control information parts are placed are aligned side by side,wherein the controller manages volumes as second logical volumes, whichincludes a plurality of groups each of which is formed from the storagearea in a real storage area of the storage devices, which comprises astorage area with a second data placement in which each of the groups isa unit at which capacity is changed, and which the storage area isincluding a second data area corresponding to the one first data areaand a second control information area corresponding to the one firstcontrol information area, and wherein if an access request for access toa data part belonging to any of the first data areas is received, thecontroller calculates a first data address of the data part belonging tothe first data area as an access destination based on the access requeston the condition that it is unnecessary to refer to a controlinformation part belonging to the first control information area,converts the calculated first data address into a second data address ofa data part belonging to the second data area of any of the groups, andexecutes data input/output processing against the second logical volumein accordance with the converted second data address.

Advantageous Effects of Invention

With the present invention, it is possible to improve read/write accessperformance from and to a disk when it is not necessary to refer to acontrol information part.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block configuration diagram showing the overallconfiguration of a storage system.

FIG. 2 is a configuration diagram showing the configuration of amicroprogram which is executed in the storage controller.

FIG. 3 is a configuration diagram showing the logical configuration inthe storage apparatus.

FIG. 4 is a configuration diagram of a management table for managingcorrespondence relationships between HDEV numbers and LDEV numbers.

FIG. 5 is a configuration diagram of a management table for managingcorrespondence relationships between LDEV numbers, volume attributes andvolume capacity.

FIG. 6 is a configuration diagram of a management table for managingcorrespondence relationships between LDEV numbers and disk numbers.

FIG. 7 is a configuration diagram of a management table for managingcorrespondence relationships between LDEV numbers and pool numbers.

FIG. 8 is a configuration diagram of a management table for managingcorrespondence relationships between pool numbers and disk numbers.

FIG. 9 is a configuration diagram illustrating data placement in a3390-format LDEV.

FIG. 10 is a configuration diagram illustrating data placement in a 3390format LDEV and in a real storage area.

FIG. 11 is a configuration diagram of a management table for managingthe sizes of distributed user data areas and distributed controlinformation areas.

FIG. 12 is a configuration diagram of a management table for managingthe addresses of distributed user data areas and distributed controlinformation areas.

FIG. 13 is a flowchart illustrating address conversion processing in afirst embodiment.

FIG. 14 is a configuration diagram illustrating data placement in a3390-A format LDEV.

FIG. 15 is a configuration diagram illustrating configuration in acylinder group.

FIG. 16 is a configuration diagram illustrating correspondencerelationships between address on a 3390 format LDEV and addresses on a3390-A format LDEV.

FIG. 17 is a configuration diagram of a management table for managingthe sizes of distributed user data areas and distributed controlinformation areas.

FIG. 18 is a configuration diagram of a management table for managingthe addresses of distributed user data areas and distributed controlinformation areas.

FIG. 19 is a flowchart showing capacity extension processing of a 3390-Aformat LDEV.

FIG. 20 is a configuration diagram illustrating correspondencerelationships following capacity extension between addresses on a 3390format LDEV and addresses on a 3390-A format LDEV.

FIG. 21 is a flowchart illustrating address conversion processing in asecond embodiment.

FIG. 22 is a configuration diagram illustrating the relationshipsbetween HDEV and LDEV in a third embodiment.

FIG. 23 is a configuration diagram of a management table for managingthe addresses of distributed user data areas and distributed controlinformation areas in the third embodiment.

FIG. 24 is a flowchart illustrating copy processing in a fourthembodiment.

FIG. 25 is a configuration diagram of a page management table.

FIG. 26 is a configuration diagram of a page management directory.

FIG. 27 is a flowchart illustrating MF host write command processing ina fifth embodiment.

FIG. 28 is a flowchart illustrating copy data reception processing in asixth embodiment.

DESCRIPTION OF EMBODIMENTS

An example of the present invention will be explained hereafter.

Note that in the following description various types of information areprovided using expressions such as Management Table however that thevarious types of information may also be expressed using data structureother than a table. Furthermore, in order to show that there is nodependence on data structure, Management Table may be referred to asManagement Information.

Furthermore, in the following description, the processing may sometimesbe described with a program as the subject. However, since the programis run by a processor, for example a CPU (Central Processing Unit),predetermined processing is executed by suitably using storage resources(memory, etc.) and a communication interface device (communication port,etc.), and hence the processor may also be the subject of theprocessing. The processor may also comprise dedicated hardware inaddition to the CPU. The computer program may be installed on eachcomputer from a program source. The program source may be storage mediaor a program distribution server, and so on.

Furthermore, each component such as LDEV (Logical DEVice), for example,can be identified by a number and so on. However, as long as theinformation allows the components to be identified, other types ofidentification information such as names may also be employed.

Embodiments of the present invention will be explained hereafter usingthe drawings. In the drawings which follow, the same reference signs areassigned to identical parts. However, the present invention is notlimited to these embodiments, rather all applications which conform tothe spirit of this invention are included in the technological scope ofthe present invention. Furthermore, absent particular limitations, eachof the components may be included as a single component or a pluralityof components.

<Overall Configuration of Storage System>

FIG. 1 shows the overall configuration of a storage system

In FIG. 1, the storage system comprises a computer system that includes,for example, a plurality of storage apparatuses 101, a plurality ofmainframe (MF) host computers 102, and a management host computer 103.

Each of the storage apparatuses 101 and MF host computers 102 areconnected via a network 111, for example, and one storage apparatus(sometimes also referred to hereafter as the first storage apparatus)101 of the plurality of storage apparatuses is connected to themanagement host computer 103 via a network 113, and so on.

The first storage apparatus 101 is connected to a different storageapparatus (sometimes also referred to hereafter as the second storageapparatus) via a network 111, and so on.

The MF host computers 102 are each connected to the network 111 via acommunication line 114.

The storage apparatuses 101 are each connected to the network 111 via acommunication line 115.

The management host computer 103 is connected to the network 113 via acommunication line 116.

The first storage apparatus 101 is connected to the network 113 via acommunication line 117.

Note that the abovementioned communication lines 114 to 117 comprise afixed line such as a metal cable or optical fiber cable, and so on.However, each of the MF host computers 102 and storage apparatuses 101,the first storage apparatus 101 and the management computer 103, andeach of the MF host computers 102 and management computer 103 can alsoeach be connected wirelessly. In this case, the communication lines 114to 117 are omitted.

Furthermore, the networks 111 and 113 may also be a common network. Thenetworks 111 and 113 are each communication networks such as SANs(Storage Area Networks) or LANs (Local Area Networks), and so on.

The configuration of each storage apparatus 101 will be explained next.

The storage apparatuses 101 each comprise, for example, one or morestorage controllers 131, and one or more disks 132. Note that thestorage apparatuses 101 each have the same configuration and thereforethe configuration of the first storage apparatus 101 will be explainedhereafter.

One or more disks 132 include, as storage devices for storing data, atleast an SSD (Solid State Drive), a SAS (Serial Attached SCSI)-HDD (HardDisk Drive), or a SATA (Serial Advanced Technology Attachment)-HDD. Notethat a physical storage device of another type may also be provided inplace of or in addition to at least one of the aforementioned disks 132.

One or more disks 132 is connected to a storage controller 131 via acommunication line 112 such as a Fibre channel cable, and so on. Notethat one or more RAID (Redundant Array of Independent Disks) groups canbe constructed from a plurality of disks 132.

The configuration of the storage controller 131 will be explained next.

The storage controller 131 controls input/output processing of data withrespect to the disk 132, that is, controls data write (writing) or read(reading) with respect to the disk 132, in accordance with commandsreceived from each MF host computer 102.

The storage controller 131 provides each MF host computer 102 which isan access request source with logical devices to which real storage areahas already been allocated, or with logical devices comprising a virtualstorage area which is used by a Thin Provisioning function (describedsubsequently), as logical devices or logical volumes which are accesstargets.

In the logical devices configured of a virtual storage area, a realstorage area may or may not have already been allocated to them.

At this point, the storage controller 31 is able to refer to andidentify the real storage area or virtual storage area by means ofcylinder head numbers (track numbers hereafter), and so on.

The storage controller 131 comprises storage resources, a communicationinterface device (an interface device is abbreviated hereafter as I/F),and a CPU 122 which is connected to the storage resources andcommunication interface device, and so on.

The storage resources are a main memory 123 and a cache memory 124, andso on.

A host I/F 121, a management host I/F 127, and a disk I/F 125 areincluded as communication I/Fs, and so on. The main memory 123, cachememory 124, CPU 122, host I/F 121, management host I/F 127, and disk I/F125 are connected to one another via a network 126 which comprises acommunication line such as a bus. The management host I/F 127 is an NIC(Network Interface Card), and so on.

The hardware configurations of each of the MF host computers 102 andmanagement host computers 103 are typically the same as the computer.That is, each of the MF host computers 102 and management host computers103 comprise a communication interface device, storage resources, and aCPU which is connected to the communication interface device and storageresources. The communication interface device is, for example, a hostbus adapter (HBA) for communicating via the network 111 and an NIC forcommunicating via the network 113. The storage resources comprise amemory and internal HDD, and so on.

FIG. 2 shows the configuration of a microprogram 231 which is executedin the storage controller 131.

In FIG. 2, one or more microprograms 231 are read by the CPU 122 to themain memory 123. The microprogram 231 comprises a command controller251, a RAID controller 252, a configuration controller 253, and anaddress conversion unit 254. Various processing which will be describedsubsequently is carried out as a result of the CPU 122 executing each ofthe controllers 251 to 254 in the microprogram 231 that is read to themain memory 123.

For instance, the cache memory 124 is arranged to be a buffer thattemporarily stores write data received from each MF host computer 102and data read from the disk 132 by the RAID controller 252 in themicroprogram 231.

The host I/F 121 is connected to each of the MF host computers 102 viathe network 111, receives access commands as access requests (writecommands or read commands) from each of the MF host computers 102, andtransfers the received access commands to the command controller 251.

The management host I/F 127 is connected to the management host computer103 via a network 113, and if an instruction to perform LDEV capacityexpansion (described subsequently) or an inter-LDEV data copyinstruction, for example, is received from the management host computer103, the management host I/F 127 transfers the received instruction tothe command controller 251 or configuration controller 253.

The disk I/F 125 sends and receives data between each of the disks 132and the storage resources (the main memory 123 and cache memory 124).The disk I/F 125 is connected to each of the disks 132 via thecommunication channel 112.

The basic operation of the storage apparatus 101 will be described nextin simple terms.

When a write command is received from any of the MF host computers 102via the host I/F 121, the storage controller 131 stores write data whichis received from the MF host computer 102 in the cache memory 124.

The storage controller 131 writes write data stored in the cache memory124 to the disk 132 via the disk I/F 125. On an aside, the configurationmay be such that the storage controller 131 informs the MF host computer102 that the write command processing is complete at the point where thewrite data is stored in the cache memory 124, or informs the MF hostcomputer 102 that the write command processing is complete at the pointthe write data is written to the disk 132.

When received a read command from the MF host computer 102, the storagecontroller 131 confirms whether or not the data (read target data)designated by the parameters in the read command is stored in the cachememory 124.

If the read target data is stored in the cache memory 124, the storagecontroller 131 reads the read target data from the cache memory 124 andtransmits the read target data thus read to the MF host computer 102 viathe host I/F 121. On the other hand, if the read target data is notstored in the cache memory 124, the storage controller 131 reads theread target data from one or more disks 132 via the disk I/F 125 andstores the read target data thus read in the cache memory 124.Thereafter, the storage controller 131 transmits read target data storedin the cache memory 124 to the MF host computer 102 via the disk I/F121.

<Logical Configuration in the Storage Apparatus>

FIG. 3 shows a logical configuration in the storage apparatus 101.

In FIG. 3, the storage apparatus 101 includes one or more host logicaldevices (hereinafter sometimes referred to as HDEV) as host logicaldevices comprising storage areas which are referred to by each of the MFhost computers 102 and the management host computer 103.

Unique HDEV numbers are assigned to the HDEV 321 in the storageapparatus 101, and the MF host computers 102 and management hostcomputer 103 and so on identify the HDEV 321 from the HDEV numbers. Forexample, an OS 331 on each of the MF host computers 102 performs readaccess or write access to the HDEV 321.

The HDEV 321 comprises an aggregate group of tracks (track1, track2, . .. ), and the cylinder head number (track number) assigned to each trackis the reference target when the MF host computers 102 and themanagement host computer 103 identify each track.

One or more logical devices (hereinafter sometimes called LDEV orvolumes) 322 are associated with the HDEV 321.

Unique LDEV numbers are assigned to the LDEV 322 in the storageapparatus 101, and the microprogram 231 identifies the LDEV 322 from theLDEV numbers.

The LDEV 322 is defined as a storage area in one or more disks 132, andso on. Furthermore, the LDEV 322 may also be defined as a storage areaconstructed from a plurality of RAID groups.

The LDEV 322 comprises a plurality of data parts 325 and a plurality ofcontrol information parts 326 which correspond to the tracks. The dataparts 325 each comprise one or more records (not shown) which correspondto the tracks (track numbers), the records each storing data read orwritten by the MF host computers 102. The control information parts 326comprise control information for accessing data parts 325 of each trackor control information for referring to or updating the data parts 325of each track.

Here, the size of all the tracks in the storage apparatus 101 is a fixedvalue. The sizes of all the data parts 325 and all the controlinformation 326 in the storage apparatus 101 are fixed values.

Unique disk numbers are assigned to the disks 132 in the storageapparatus 101, and the microprogram 231 identifies each of the disks 132from the disk numbers.

Furthermore, the LDEV 322 may be saved in a virtual volume that is usedby a Thin Provisioning function (described subsequently).

The virtual volumes where the data of the LDEV 322 is saved areassociated with a pool 323 which provides a real storage area to thevirtual volume.

Unique pool numbers are assigned to the pools 323 in the storageapparatuses 101, and the microprogram 231 identifies the pool 323 fromthe pool numbers.

The pools 323 comprise one or more disks 132. The pools 323 may alsocomprise one or more RAID groups. One or more disks 132 may be installedinside or outside the storage apparatuses.

FIG. 4 shows a configuration of a management table 400 for managingcorrespondence relationships between the HDEV numbers and LDEV numbers.

The management table 400 comprises an HDEV number field 401 and an LDEVnumber field 402. The HDEV number is a number for uniquely identifyingthe HDEV 321 in the storage apparatus 101 and each entry in the HDEVnumber field 401 stores a number which corresponds to a HDEV 321. TheLDEV number is a number for uniquely identifying the LDEV 322 in thestorage apparatus 101 and each entry in the LDEV number field 402 storesa number which corresponds to an LDEV 322.

FIG. 5 shows a configuration of a management table 500 for managingcorrespondence relationships between the LDEV numbers and volumeattributes.

The management table 500 comprises an LDEV number field 501, a volumeattribute field 502, and a volume capacity field 503. The LDEV number isa number for uniquely identifying the LDEV 322 in the storage apparatus101 and each entry in the LDEV number field 501 stores a number whichcorresponds to an LDEV 322. Where volume attributes are concerned, thevolume attribute of the LDEV 322 specifies whether the volume is anormal volume or virtual volume, and each entry of the volume attributefield 502 stores the name of a normal volume or a virtual volume.

When the volume attribute of the LDEV 322 is a normal volume, thisindicates that the LDEV 322 is a volume that comprises a real storagearea in one or more disks 132.

The volume capacity is the maximum capacity of data which can be storedin a normal volume or virtual volume and each entry in the volumecapacity field 503 stores a numerical value for the capacity of thenormal volume or virtual volume.

FIG. 6 shows a configuration of a management table 600 for managingcorrespondence relationships between the LDEV numbers and disk numbers.

The management table 600 is a management table for when the volumeattribute of the LDEV 322 is a normal volume and comprises an LDEVnumber field 601 and disk number field 602. The LDEV number is a numberfor uniquely identifying the LDEV 322 in the storage apparatus 101 andeach entry in the LDEV number field 601 stores a number whichcorresponds to an LDEV 322. The disk number is a number for uniquelyidentifying the disks 132 in the storage apparatus 101 and the entriesin the disk number field 602 each store the numbers of the disks 132which the LDEV 322 comprises.

FIG. 7 shows a configuration of a management table 700 for managingcorrespondence relationships between the LDEV numbers and pool numbers.

The management table 700 is a management table for when the volumeattribute of the LDEV 322 is a virtual volume and comprises an LDEVnumber field 701 and pool number field 702. The LDEV number is a numberfor uniquely identifying the LDEV 322 in the storage apparatus 101 andeach entry in the LDEV number field 701 stores a number whichcorresponds to an LDEV 322. The pool number is a number for uniquelyidentifying the pools 323 in the storage apparatuses 101 and each entryin the pool number field 702 stores a number of a pool 323 whichcorresponds to an LDEV 322.

FIG. 8 shows a configuration of a management table 800 for managingcorrespondence relationships between the pool numbers and disk numbers.

The management table 800 is a management table for when the volumeattribute of the LDEV 322 is a virtual volume and comprises a poolnumber field 801 and disk number field 802. The pool number is a numberfor uniquely identifying the pools 323 in the storage apparatuses 101and each entry in the pool number field 801 stores a number whichcorresponds to a pool 323. The disk number is a number for uniquelyidentifying the disks 132 in the storage apparatus 101 and the entriesin the disk number field 602 each store the numbers of the disks 132from which real storage area has been assigned to the pool 323.

Embodiment 1

This embodiment is configured such that data parts and controlinformation parts are stored in different areas and if only the dataparts are read/written from the disk, the storage controller is able toposition the disk head directly at the data part, dispensing with theprocessing to skip the position of the control information part.

Here, user data areas where data parts are placed and controlinformation areas which are storage areas disposed successively to theuser data areas and in which control information parts are disposed aremanaged as storage areas which are targeted for changes in capacity, forexample storage areas when expanding or reducing capacity, and as thestorage areas, volumes (LDEV) in which user data areas and controlinformation areas lie side by side (first data placement) are managed as3390-format volumes.

<Data Placement in 3390 Format LDEV 322>

FIG. 9 shows data placement in a 3390-format LDEV 322 which the HDEV 321comprises.

In FIG. 9, the storage area 901 of the LDEV 322 comprises a user dataarea 902 and a control information area 903. The user data area 902comprises a first data area for storing a plurality of data parts(including one or more records corresponding to tracks) 325, and thecontrol information area 903 is successive to the user data area 902 andcomprises a first control information area for storing controlinformation parts 326 which comprise control information for accessingeach of the data parts 325 stored in the user data area 902. Here, thestorage controller 131 manages the LDEV 322 in a first volume format(also called 3390-format hereafter) in which the first data placementinvolves data placement of the storage area 901 in which the controlinformation area 903 is placed successively to the user data area 902.The microprogram 231 identifies the data parts 325 in each track bymeans of a track number and identifies the control information part 326in each track by means of a track number.

The 3390-format LDEV 322 is such that as the number of tracks in an HDEV321 increases, the numbers of tracks in the user data area 902 and thecontrol information area 903 also increase. That is, in a 3390-formatLDEV 322 is such that of the number of tracks in an HDEV 321 increasesas the capacity expands, the numbers of tracks in the user data area 902and the control information area 903 also increase as the track numberin the HDEV 321 increases.

For the data placement of the 3390-format LDEV 322, the controlinformation area 903 can also be placed in front of the user data area902.

<Example of a Write Command or Read Command with Respect to a3390-Format LDEV 322>

Processing is described hereafter for a case where an MF host computer102 issues a write command to the storage controller 131 via the hostI/F 121. The write command parameters are the HDEV number, the tracknumber of the write target track in the HDEV 321, and the write targetdata.

If a write command is received from the MF host computer 102, thecommand controller 251 in the storage controller 131 refers to themanagement table 400 based on the HDEV number which is a write commandparameter, and acquires the LDEV number corresponding to the HDEVnumber.

The command controller 251 specifies the LDEV 322 from the acquired LDEVnumber, and calculates, based on the track number of the write targettrack, the address of the data part 325 of the specified track number onthe LDEV 322 (the same track number as the track number of the writetarget track in the HDEV 321) and the address of the control informationpart 326 of the specified track number on the LDEV 322 (the same tracknumber as the track number of the write target track in the HDEV 321).

Thereafter, the command controller 251 determines whether theaforementioned write command must refer to the control information part326 of the track number. If it is necessary to refer to the controlinformation part 326 of the track number, for example in a case wherethe MF host computer 102, as a result of referring to the controlinformation part 326, requests that information be sent back relating tothe alignment state of the head with respect to the track, the RAIDcontroller 252 refers to the management table 600 based on the LDEVnumber and reads, based on the address of the control information part326, the control information part 326 of the track number from one ormore disks 132 to the cache memory 124. The command controller 251refers to the control information part 326 of the track number which isread to the cache memory 124.

If there is no need for the command controller 251 to refer to thecontrol information part 326 of the track number, the read processing ofthe control information part 326 may be omitted.

That is, if data parts 325 and control information parts 326 are storedin different areas and the sizes of the tracks storing the data parts325 have a configured value, the command controller 251 directlypositions the disk head at the data parts 325 on the disk side evenwithout referring to the control information of the control informationparts 326. In this case, processing to skip areas of control informationparts 326 is unnecessary in disk head alignment, and the storagecontroller 131 is able to perform faster read access or write accessprocessing than when referring to the control information part 326.

Thereafter, the command controller 251 writes write target data to thecache memory 124.

The RAID controller 252 subsequently refers to the management table 600based on the LDEV number, acquires the disk number corresponding to theLDEV number, specifies the disk 132 comprising the LDEV 322, and basedon the address of the data part 325, writes the write target data in thecache memory 124 to one or more specified disks 132. That is, if the3390-format data placement is the same as the data placement in a realstorage area, the RAID controller 252 is able to write the write targetdata in the cache memory 124 to one or more specified disks 132 by usingthe address according to the result of the calculation by the commandcontroller 251 without using the address obtained in the addressconversion by the address conversion unit 254.

Thereafter, the storage controller 131 informs the MF host computer 102that the write command processing is complete via the host I/F 121.

Processing was described hereinabove for a case where an MF hostcomputer 102 issues a write command to the storage controller 131 viathe host I/F 121.

Processing is described hereafter for a case where an MF host computer102 issues a read command to the storage controller 131 via the host I/F121. The read command parameters are the HDEV number and the tracknumber of the read target track in the HDEV 321.

If a read command is received from the MF host computer 102, the commandcontroller 251 in the storage controller 131 refers to the managementtable 400 based on the HDEV number which is a read command parameter,and acquires the LDEV number corresponding to the HDEV number.

The command controller 251 specifies the LDEV 322 from the acquired LDEVnumber, and calculates, based on the track number of the read targettrack (the same track number as the track number of the read targettrack in the HDEV 321), the address of the data part 325 of thespecified track number on the LDEV 322 and the address of the controlinformation part 326 of the track number on the read target track (thesame track number as the track number of the read target track in theHDEV 321).

Thereafter, the command controller 251 determines whether theaforementioned read command must refer to the control information part326 of the track number. If it is necessary to refer to the controlinformation part 326 of the track number, the RAID controller 252 refersto the management table 600 based on the LDEV number and reads, based onthe address of the control information part 326, the control informationpart 326 of the track number from one or more disks 132 to the cachememory 124. The command controller 251 refers to the control informationpart 326 of the track number which is read to the cache memory 124. Ifthere is no need to refer to the control information part 326 of thetrack number 942, the read processing of the control information part326 may be omitted.

The RAID controller 252 subsequently refers to the management table 600based on the LDEV number, acquires the disk number corresponding to theLDEV number and specifies the disk 132, and based on the address of thedata part 325, reads the data part of the track number of the readtarget track to the cache memory 124 from one or more specified disks132.

Thereafter, the storage controller 131 transmits a data part 325, in thecache memory 124, which has the track number of the read target track tothe MF host computer 102 via the host I/F 121.

Processing was described hereinabove for a case where an MF hostcomputer 102 issues a read command to the storage controller 131 via thehost I/F 121.

In the processing in response to a read command, if the data part 325 orcontrol information part 326 of the track number of the read targettrack already exists in the cache memory 124, the processing can beomitted in which the data part 325 or control information part 326 ofthe track number of the read target track is read to the cache memory124 from one or more disks 132.

Also, in the processing in response to a read command, because the diskhead can be directly aligned at the data part 325 without the commandcontroller 251 referring to the control information of the controlinformation part 326, the storage controller 131 is able to expediteread access or write access processing because the processing to skipthe control information part 326 is unnecessary when the controlinformation part 326 is not referred to.

<Capacity Expansion of the 3390 Format LDEV 322>

FIG. 10 shows an example of when capacity expansion is carried out onthe 3390-format LDEV 322.

If a need arises to change the capacity of the 3390-format LDEV 322, forexample if a need arises to expand the capacity of the 3390 format LDEV322 shown in FIG. 9, the access request source can be identified withthe access target volume serving as the 3390-format volume and thecommand controller 251, and data placement is adopted in which a controlinformation area is formed successive to a user data area so that thecommand controller 251 is able to access the LDEV 322 as a 3390 formatLDEV 322 even after capacity expansion.

More specifically, the storage area 910 of the 3390 format LDEV 322after capacity expansion comprises distributed user data areas 1001 and1002, and distributed control information areas 1011 and 1012.

In other words, the storage area of the LDEV 322 before capacityexpansion comprises distributed user data area 1001 and distributedcontrol information area 1011, and if a distributed user data area 1002and a distributed control information area 1012 are added to the storagearea, data placement (data placement according to the 3390 format) iscarried out such that the distributed user data area 1002 is placed as anewly secured user data area 1002 successively to the distributed userdata area 1001, the distributed control information area 1011 is placedsuccessively to the distributed user data area 1002, and the distributedcontrol information area 1012 is placed as a newly secured storage areasuccessively to the distributed control information area 1011, andtaking the storage area 910 as a whole, the control information area isformed successively to the user data area.

However, the real storage area 920 constructed on the disk 132 is formedby the distributed user data area 1001, the distributed controlinformation area 1011, the distributed user data area 1002, and thedistributed control information area 1012 in that order.

In other words, the storage area of the real storage area beforecapacity expansion comprises the distributed user data area 1001 and thedistributed control information area 1011, and if a distributed userdata area 1002 and a distributed control information area 1012 are addedto the storage area, data placement is carried out such that thedistributed user data area 1002, which is a newly secured storage area,is placed successively to the distributed control information area 1011,and the distributed control information area 1012, which is a newlysecured storage area, is placed successively to the distributed userdata area 1002.

Here, if the configuration controller 253 in the microprogram 231receives a capacity expansion instruction from the management hostcomputer 103 via the management host I/F 127, a newly secured realstorage area is formed as a real storage area which is successive to thedistributed control information area 1011, and the distributed user dataarea 1002 and the distributed control information area 1012 are placedsuccessively to the real storage area.

The distributed user data areas 1001 and 1002 and the distributedcontrol information areas 1011 and 1012 can have the same configurationas the user data area 902 and control information area 903 in thestorage area 901 in FIG. 9.

The data placement for a real storage area comprising two areas, namelythe distributed user data area 1001 and distributed control informationarea 1011 in the real storage area 920 is 3390-format data placement,and the data placement for a real storage area comprising two areas,namely the distributed user data area 1002 and distributed controlinformation area 1012 is 3390-format data placement. That is, there aretwo classes of 3390-format data placement in the real storage area 920.

The size of the distributed user data area 1002 is determined by theexpansion capacity designated on the management screen of the managementhost computer 103 and is an integer multiple of the aforementioned tracksize, and so on.

The ratio between the size of the distributed user data area 1001 andthe size of the distributed control information area 1011 is equal tothe ratio between the size of the distributed user data area 1002 andthe size of the distributed control information area 1012.

Furthermore, the track number of the data part 325 indicated by anaddress 1021 in the distributed user data area 1002 placed in thestorage area 910 is equal to the track number of the data part 325indicated by the address 1022 in the distributed user data area 1002placed in the real storage area 920.

In FIG. 10, data is placed in the real storage area 920 after capacityexpansion, namely the distributed user data area 1001, the distributedcontrol information area 1011, the distributed user data area 1002, andthe distributed control information area 1012 in that order (hereinafterdata placement will sometimes be referred to as data placement in a realstorage area.).

In cases where data placement of the storage area 910 to which thecommand controller 251 refers differs from the data placement of thereal storage area 920, the address (hereinafter also called the dataaddress) 1021 indicated by the data part 325 of the track number in thestorage area 910, which is 3390-format data placement, and the address(hereinafter sometimes also called the data address) 1022 indicated bythe data part 325 of the track number in the real storage area 920,which is data placement in a real storage area, have different addressvalues in each distributed user data area 1002 despite having the sametrack number. Therefore the address conversion unit 254 in themicroprogram 231 executes address conversion for converting the address1021 indicating the data part 325 of the track number in the distributeduser data area 1002 of the storage area 910, for example, into theaddress 1022 indicating the data part 325 of the track number in thereal storage area 920.

Likewise, the address conversion unit 254 in the microprogram 231performs address conversion for converting an address (hereinaftersometimes also referred to as the control information address)indicating the control information part 326 of the track number in thestorage area 910 in 3390 format data placement into an address(hereinafter sometimes also referred to as the control informationaddress) indicating the control information part 326 of the track numberof the real storage area 920 which is data placement in the real storagearea.

Even after capacity expansion of the LDEV 322, the command controller251 is able to access a volume according to data placement in the realstorage area as a 3390 format volume by using an address obtainedthrough the address conversion by the address conversion unit 254.

<Address Conversion Processing of the Address 1021 in 3390 Format DataPlacement and of the Address 1022 in Data Placement in the Real StorageArea>

FIG. 11 shows a configuration of a management table 1100 for managingthe sizes of distributed user data areas and distributed controlinformation areas.

In FIG. 11, the management table 1100 is a table stored in the mainmemory 123 or cache memory 124 and which comprises an ifield 1101, asize field 1102 of a distributed user data area i, and a size field 1103of a distributed control information area i. A number identifying thedistributed user data area and distributed control information area isstored in each entry of the ifield 1101. The sizes of the distributeduser data areas 1001 and 1002 are stored as numerical values (150, 100),for example, in each entry of the distributed user data area i sizefield 1102. The sizes of the distributed control information areas 1011and 1012 are stored as numerical values (15, 10), for example, in eachentry of the distributed control information area i size field 1103.

Information relating to the sizes of the distributed user data area andthe distributed control information area is added to the entries of themanagement table 1100 each time capacity expansion of the aforementioned3390 format volume is carried out.

The sizes of the distributed user data areas and the sizes of thedistributed control information areas in each entry of the managementtable 1100 in FIG. 11 are not fixed. However, the ratio between thesizes of the distributed user data areas and the sizes of thedistributed control information areas in each entry of the managementtable 1100 is constant.

FIG. 12 shows a configuration of a management table 1200 for managingthe addresses of distributed user data areas and distributed controlinformation areas.

In FIG. 12, the management table 1200 comprises an ifield 1201, adistributed user data area i start address field (3390 format) 1202, adistributed user data area i start address field (data placement in thereal storage area) 1203, a distributed control information area i startaddress field 1204, and a distributed control information area i startaddress field (data placement in real storage area) 1205, and themanagement table 1200 is stored in the main memory 123 or cache memory124, and so on.

A number identifying the distributed user data area and distributedcontrol information area is stored in each entry of the ifield 1201. Thestart addresses of the distributed user data areas 1001 and 1002 in thestorage area 910 are stored as numerical values (0, 150), for example,in each entry of the distributed user data area i start address field1202. The start addresses of the distributed user data areas 1001 and1002 in the real storage area 920 are stored as numerical values (0,165), for example, in each entry of the distributed user data area istart address field 1203.

The start addresses of the distributed control information areas 1011and 1012 in the storage area 910, for example, are stored as numericalvalues (250, 265), for example, in each entry of the distributed controlinformation area i start address field 1204. The start addresses of thedistributed control information areas 1011 and 1012 in the real storagearea 920, for example, are stored as numerical values (150, 165), forexample, in each entry of the distributed control information area istart address field 1205.

Information relating to the start addresses of the distributed user dataarea and the distributed control information area is added to theentries of the management table 1200 each time capacity expansion of theaforementioned 3390 format volume is carried out.

Processing for calculating an address indicating the data part 325 ofthe track number for data placement in the real storage area 920 from anaddress indicating the data part 325 of the track number in theaforementioned 3390 format data placement will be described next inaccordance with the flowchart in FIG. 13.

At first, the address conversion unit 254 in the microprogram 231 sets ito 0 (S11) and refers to the management tables 1100 and 1200 to acquireinformation relating to the start address and size of the 0th (ith)distributed user data area in 3390 format (S12), and then determineswhether or not the address 1021 in the distributed user data area 1002in the storage area 910, for example, is included in the 0th (ith)distributed user data area (S13), and when a negative determinationresult is obtained in step S13, the address conversion unit 254increments i (for example, sets i to 1) (S14), and repeats theprocessing of S12 to S14 until an affirmative determination result isobtained in step S13.

If an affirmative determination result is obtained in step S13, forexample if the address 1021 in the distributed user data area 1002 inthe storage area 910 is contained in the second distributed user dataarea 1002, the address conversion unit 254 calculates the number (2) ofthe distributed user data area 1002 in which the address 1021 iscontained, and an offset address from the start address of thedistributed user data area 1002 to the address 1021 on the basis of thesizes of each of the distributed user data area and distributed controlinformation area stored in the management table 1100, the addresses ofeach of the distributed user data area and distributed controlinformation area stored in the management table 1200, and the address1021 indicating the data part 325 with a track number in the 3390-formatdata placement (S15).

The address conversion unit 254 subsequently refers to the managementtable 1200 on the basis of the addresses of the distributed user dataarea and distributed control information area, the number (2) of thedistributed user data area 1002, and acquires the start address of thedistributed user data area 1002 indicated by the number (2) of thedistributed user data area 1002 (the start address of the distributeduser data area 1002 in the real storage area 920) (S16).

Finally, the address conversion unit 254 calculates the address 1022indicating the data part 325 of the track number in the real storagearea 920 on the basis of the start address of the distributed user dataarea 1002 in the real storage area 920 and an offset address from thestart address in the storage area 910 to the address 1021 (S17).

By executing the aforementioned processing, the address conversion unit254 is able to convert the address 1021 indicating the data part 325 ofthe track number in 3390 format data placement into an address 1022indicating the data part 325 of the track number in data placement inthe real storage area 920.

Furthermore, by executing the same processing as the processing toconvert the address 1021 into the address 1022, the address conversionunit 254 is able to calculate an address indicating the controlinformation part 326 of the track number in the real storage area 920from an address indicating the control information part 326 of the tracknumber 1031 in 3390 format data placement.

According to this embodiment, by skipping the control information part326 of the track, the overhead of processing to align the disk head withthe data part 325 is reduced, and therefore the storage controller 131is able to improve the read-access or write access performance withrespect to the disk over and above the performance when the trackcontrol information part 326 is referred to.

Furthermore, according to this embodiment, even if the capacity of the3390 format storage area 910 is expanded, the address 1021 indicatingthe data part 325 of the track number in 3390 format data placement canbe converted into an address 1022 indicating the data part 325 of thetrack number for data placement in the real storage area 920 and theaddress indicating the control information part 326 of the track numberin 3390 format data placement can be converted into an addressindicating the control information part 326 of the track number in thereal storage area 920.

Even after capacity expansion of the LDEV 322, which is 3390 format dataplacement, the command controller 251 is able to access a volumeaccording to data placement in the real storage area as a 3390 formatvolume by using an address obtained through the address conversion bythe address conversion unit 254.

Embodiment 2

This embodiment creates one cylinder group (CG) from one distributeduser data area (second data area) and one distributed controlinformation area, groups together a plurality of cylinder groups, andmanages the cylinder groups as capacity expansion unit storage areas,and as the storage areas, manages volumes, for which data placement(second data placement) is adopted in which a plurality of cylindergroups form a line, as second volume format (hereinafter also referredto as 3390-A format) volumes (LDEV 322), and converts addressespertaining to 3390-format volumes to addresses pertaining to 3390-Aformat volumes.

<Data Placement in 3390-A Format LDEV 322>

FIG. 14 shows data placement in a 3390-format LDEV 322.

In FIG. 14, the real storage area 930 of the LDEV 322 comprises acylinder group (CG) 1421 which includes a distributed user data area1401 and a distributed control information area 1411 which is placedsuccessively to the distributed user data area 1401, and a cylindergroup (CG) 1422 which includes a distributed user data area 1402 and adistributed control information area 1412 which is placed successivelyto the distributed user data area 1402. The distributed user data areas1401 and 1402 are each of the same size and the distributed controlinformation areas 1411 and 1412 are also of the same size. That is, thecylinder groups (CG) 1411 and 1422 each comprise the same size and thecapacities of the cylinder groups are the units of capacity expansion.

Here, the storage controller 131 manages, for example, the LDEV 322 in asecond volume format (also called 3390-A format hereafter) in which thesecond data placement involves data placement of the real storage area930 in which the distributed control information area (second controlinformation area) 1411 is placed successively to the distributed userdata area (second data area) 1401, these storage areas forming thecylinder group (CG) 1421.

The one or plurality of CG 1421 which the 3390-A format LDEV 322comprises may also be referred to by their CG number. The one orplurality of distributed user data areas 1401 which the LDEV 322comprises may also be referred to by the number of the distributed userdata area (described subsequently). The one or plurality of distributedcontrol information areas 1411 which the LDEV 322 comprises may also bereferred to by the number of the distributed control information area(described subsequently).

FIG. 15 shows the configuration in the cylinder group 1421.

The cylinder group (CG) 1421 comprises the distributed user data area1401 and the distributed control information area 1411. The distributeduser data area 1401 comprises a second data area for storing a plurality(D) of data parts (including one or more records corresponding to tracks1 to D) 325.

The distributed control information area 1411 is placed successively tothe distributed user data area 1401 and comprises a plurality (D) ofcontrol information parts 326 which comprise control information foraccessing each of the data parts 325 stored in the distributed user dataareas 1401, a plurality (D) of record existence information parts 327comprising record existence information indicating whether a recordexists in each track of each data part 325, storage function managementinformation 328 with which the storage controller 131 manages the LDEV322, and a second control information area in which the storagecontroller 131 stores expansion mode determination information 329 fordetermining whether or not a mode for expanding cylinder groups exists.

Here, the microprogram 231 identifies the data parts 325 in each trackby means of a track number and identifies the control information part326 in each track by means of a track number.

The control information parts 326 and the record existence informationparts 327 can also comprise bitmaps, and so on. One or more records aresaved in the data parts 325 of each track. The records are write dataand so forth from the MF host computers 102, and so on.

In addition, in each of the cylinder groups 1421 and 1422, the number(D) of data parts 325 of the tracks in the distributed user data areas1401 and 1402, the number (D) of control information parts 326 of thetracks in the distributed control information areas 1411 and 1412, andthe number (D) of record existence information parts 327 of the tracksin the distributed control information areas 1411 and 1412 are equal.

FIG. 16 shows correspondence between addresses in a 3390 format LDEV 322and addresses in a 3390-A format LDEV 322.

In FIG. 16, the storage area 910 of the 3390 format LDEV 322 comprisesthe distributed user data areas 1401, 1402, and 1403 and distributedcontrol information areas 1411, 1412, and 1413, and the real storagearea 930 of the 3390-A format LDEV comprises the cylinder group 1421which includes the distributed user data area 1401 and distributedcontrol information area 1411, the cylinder group 1422 which includesthe distributed user data area 1402 and distributed control informationarea 1412, and the cylinder group 1423 which includes the distributeduser data area 1403 and distributed control information area 1413.

3390-format volume data placement is in the order of the distributeduser data area 1401, the distributed user data area 1402, thedistributed user data area 1403, the distributed control informationarea 1411, the distributed control information area 1412, and thedistributed control information area 1413, and 3390-A format volume dataplacement is in the order of the cylinder group 1421, cylinder group1422, and cylinder group 1423.

In cases where a different structure is adopted for 3390 format volumedata placement and 3390-A format data placement, an address indicating adata part 325 with a track number in the storage area 910, which is3390-format data placement, and an address indicating a data part 325with a track number in the real storage area 930, which is 3390-A dataplacement, have different address values in each distributed user dataarea and each distributed control information area despite having thesame track number. Therefore the address conversion unit 254 in themicroprogram 231 executes address conversion for converting the address1031 indicating the data part 325 of the track number in the distributeduser data area 1403 of the storage area 910, for example, into theaddress 1032 indicating the data part 325 of the track number in thereal storage area 930.

Likewise, the address conversion unit 254 in the microprogram 231performs address conversion for converting an address indicating thecontrol information part 326 of the track number in the storage area 910in 3390 format data placement into an address indicating the controlinformation part 326 of the track number in the real storage area 930which is 3390-A format data placement.

The command controller 251 is able to access an LDEV 322 according to3390-A format data placement in the real storage area as a 3390 formatLDEV 322 by using an address obtained through the address conversion bythe address conversion unit 254. That is, despite accessing the LDEV 322of 3390 format data placement, the command controller 251 is able toaccess the data part 325 in the real storage area as a result ofconversion by the address conversion unit 254 of the address in the LDEV322 of 3390 format data placement to the address of the LDEV 322according to 3390-A format data placement.

<Capacity Expansion of the 3390-A Format LDEV 322>

FIG. 17 shows a configuration of a management table 1700 for managingthe sizes of distributed user data areas and distributed controlinformation areas.

In FIG. 17, the management table 1700 is a table for managing a 3390-Aformat LDEV 322, the table 1700 comprising a distributed user data arealength field 1701 and a distributed control information area lengthfield 1702, and being stored in the main memory 123 or cache memory 124,and so on. The entries of the distributed user data area length field1701 store information, as numerical values, which indicates the commonlengths of each distributed user data area. The entries of thedistributed control information area length field 1702 storeinformation, as numerical values, which indicates the common length ofeach distributed control information area.

FIG. 18 shows a configuration of a management table 1800 for managingthe addresses of distributed user data areas and distributed controlinformation areas.

In FIG. 18, the management table 1800 comprises an ifield 1801, a startaddress field of the distributed user data area i (3390 format) 1802, astart address field of the distributed user data area i (3390-A formatdata placement) 1803, a start address field of the distributed controlinformation area i 1804, and a start address field of the distributedcontrol information area i (3390-A format data placement) 1805, and themanagement table 1800 is stored in the main memory 123 or cache memory124, and so on.

A number identifying the distributed user data area and distributedcontrol information area is stored in each entry of the ifield 1201. Thestart addresses of the distributed user data areas 1401 and 1002 in thestorage area 910 are stored as numerical values (0, 100), for example,in each entry of the start address field of the distributed user dataarea i 1802. The start addresses of the distributed user data areas 1401and 1402 in the real storage area 930 are stored as numerical values (0,150), for example, in each entry of the start address field of thedistributed user data area i 1803.

The start addresses of the distributed control information areas 1411and 1412 in the storage area 910 are stored as numerical values (500,550), for example, in each entry of the start address field of thedistributed control information area i 1804. The start addresses of thedistributed control information areas 1411 and 1412 in the real storagearea 930 are stored as numerical values (100, 250), for example, in eachentry of the start address field of the distributed control informationarea i 1805.

Information relating to the start addresses of each of the distributeduser data areas and distributed control information areas is added tothe entries of the management table 1800 each time capacity expansion ofa 3390 format volume is carried out.

Capacity expansion processing of a 3390-A format LDEV 322 will beexplained next with reference to the flowchart in FIG. 19.

When the management host computer 103 issues an capacity expansioninstruction for the LDEV 322 to the configuration controller 253 via themanagement host I/F 127, the configuration controller 253 refers to themanagement table 1700 and acquires the size (100) of the distributeduser data area and the size (50) of the distributed control informationarea (S21).

Next, the configuration controller 253 checks whether or not theexpansion capacity designated by the management host 103 is an integermultiple of the size (100) of the acquired distributed user data area(S22).

If the expansion capacity designated via the management screen is not aninteger multiple of the size (100) of the distributed user data area,the configuration controller 253 informs the management host computer103 via the management host I/F 127 that the capacity expansion of theLDEV 322 has failed, and ends the capacity expansion processing.

However, if the expansion capacity is an integer multiple of the size(100) of the distributed user data area, the configuration controller253 renders a quotient which is obtained by dividing the expansioncapacity by the size (100) of the distributed user data area as thenumber of expansion cylinder groups, and saves this quotient in the mainmemory 123.

Thereafter, the configuration controller 253 secures a storage area(hereinafter also known as the expansion CG area) in which cylindergroups (CG) can be saved according to the number of expansion cylindergroups (S23). In this case, in the capacity expansion, the size of thesecured expansion CG area is an integer multiple of the size of the CGwhich is the pre-expansion area capacity unit.

The configuration controller 253 subsequently determines whether or notthe securing of the CG area corresponding to the capacity for expansionhas been successful (S24), and if the expansion CG area has failed, theconfiguration controller 253 informs the management host computer 103,via the management host I/F 127, that capacity expansion of the LDEV 322has failed, and ends the capacity expansion processing.

If the securing of the expansion CG area is successful, theconfiguration controller 253 configures the changed size to the volumecapacity in the volume management information (S25), informs the MF hostcomputer 102 via the host I/F 121 that the capacity has changed and thatcapacity expansion has been successful, and ends the processing of thisroutine.

Note that one or more distributed control information areas which existin the expansion CG area may or may not be pre-initialized.

Furthermore, the capacity expansion instruction may be issued while thestorage system, which comprises the MF host computers 102 and storageapparatuses 101, is online.

FIG. 20 shows correspondence, after capacity expansion, betweenaddresses in a 3390 format LDEV 322 and addresses in a 3390-A formatLDEV 322.

Upon receiving a capacity expansion instruction from the management hostcomputer 103 via the management host I/F 127, the configurationcontroller 253 in the microprogram 231 places the distributed user dataareas 1404 and 1405 after the distributed user data area 1403 as dataplacement on the 3390 format LDEV 322, and places the expansion cylindergroups 1424 and 1415 as newly secured real storage area after thecylinder group 1423 as data placement on a 3390-A format LDEV 322.

In FIG. 20, the storage area 910 of the 3390 format LDEV 322 comprisesthe distributed user data areas 1401, 1402, 1403, 1404, and 1405 and thedistributed control information areas 1411, 1412, 1413, 1414, and 1415and the real storage area 930 of the 3390-A format LDEV comprises thecylinder group 1421 which includes the distributed user data area 1401and distributed control information area 1411, the cylinder group 1422which includes the distributed user data area 1402 and distributedcontrol information area 1412, the cylinder group 1423 which includesthe distributed user data area 1403 and distributed control informationarea 1413, the cylinder group 1424 which includes the distributed userdata area 1404 and distributed control information area 1414, and thecylinder group 1425 which includes the distributed user data area 1405and distributed control information area 1415.

3390-format volume data placement is in the order of the distributeduser data area 1401, the distributed user data area 1402, thedistributed user data area 1403, the distributed user data area 1404,and the distributed user data area 1405, and the distributed controlinformation area 1411, the distributed control information area 1412,the distributed control information area 1413, the distributed controlinformation area 1414, and the distributed control information area1415, and 3390-A format volume data placement for the real storage areais in the order of the cylinder group (CG) 1421, cylinder group 1422,cylinder group 1423, expansion cylinder group 1424, and expansioncylinder group 1425.

In cases where a different structure is adopted for 3390 format volumedata placement and 3390-A format data placement, an address indicating adata part 325 with a track number in the storage area 910, which is3390-format data placement, and an address indicating a data part 325with a track number in the real storage area 930, which is 3390-A dataplacement, have different address values in each distributed user dataarea and each distributed control information area despite having thesame track number. Therefore the address conversion unit 254 in themicroprogram 231 executes address conversion for converting the address1051 indicating the data part 325 of the track number in the distributeduser data area 1405 of the storage area 910, for example, into theaddress 1052 indicating the data part 325 of the track number in thereal storage area 930.

Likewise, the address conversion unit 254 in the microprogram 231performs address conversion for converting an address indicating thecontrol information part 326 of the track number in the storage area 910in 3390 format data placement into an address indicating the controlinformation part 326 of the track number in the real storage area 930which is 3390-A format data placement.

The command controller 251 is also able, after capacity expansion of3390-A format LDEV 322, to access an LDEV 322 according to 3390-A formatdata placement in the real storage area as a 3390 format LDEV 322 byusing an address obtained through the address conversion by the addressconversion unit 254.

Processing for calculating the address 1052 indicating the data part ofthe track number on the 3390-A format volume from the address 1051indicating the data part of the track number on the 3390 format volumewill be described next in accordance with the flowchart in FIG. 21.

The address conversion unit 254 in the microprogram 231 starts theaddress conversion processing, and based on the address 1051 indicatingthe data part 325 of the track number in 3390 format data placement,refers to the management table 1700 and management table 1800, andcalculates the number (5) of the 3390 format distributed user data area1405 containing the address 1051, and an offset address from the startaddress (400) of the 3390-format distributed user data area 1405 to theaddress 1051 (S31).

The address conversion unit 254 subsequently refers to the managementtable 1800 on the basis of the number (5) of the 3390-format distributeduser data area 1405, and the offset address from the start address (400)of the 3390-format distributed user data area 1405 to the address 1051,and acquires the start address (600) of the 3390-A format distributeduser data area 1405 indicated by the number (5) of the distributed userdata area 1405 (S32).

Finally, the address conversion unit 254 calculates the address 1052indicating the data part 325 with the 3390-A format track number on thebasis of the start address (600) of the acquired 3390-A formatdistributed user data area 1405 and the offset address from the startaddress (400) of the 3390 format distributed user data area 1405 to theaddress 1051 (S33), and ends the processing of this routine.

Likewise, the address conversion unit 254 is also able to calculate anaddress indicating the control information part 326 with the 3390-Aformat track number from an address indicating the control informationpart 326 of the track number in 3390 format data placement.

<Example of a Read Command with Respect to a 3390-A Format LDEV 322>

Processing is described hereafter for a case where the storagecontroller 131 receives a read command from an MF host computer 102 viathe host I/F 121.

The command controller 251 in the microprogram 231 calculates theaddress of the data part 325 of the track number of the read targettrack in the 3390 format LDEV 322, and informs the address conversionunit 254 of the calculation result.

The address conversion unit 254 then calculates, based on the addressobtained in this calculation, the address of the data part 325 and theaddress of the control information part 326 of a track in the realstorage area, and informs the command controller 251 of these values.Here, the data placement in the real storage area of the LDEV 322 isimplemented according to the 3390-A format.

If the data part 325 of the track number indicated by the addressreceived by the command controller 251 and the control information part326 of the track number indicated by the address received by the commandcontroller 251 are not stored, the command controller 251 instructs theRAID controller 252 to execute data reading. The RAID controller 252reads data corresponding to each address from one or more disks 132 viathe disk I/F 125 and stores each of the data thus read in the cachememory 124.

If the data part 325 of the track number indicated by the addressreceived by the command controller 251 and the control information part326 of the track number indicated by the address received by the commandcontroller 251 are stored, the command controller 251 reads the datapart 325 with the track indicated by the address from the cache memory124, and after checking the value of the control information of thetrack indicated by the address, transmits the data part 325 read fromthe cache memory 124 to the MF host computer 102 via the host I/F 121.

Processing relating to address conversion of the aforementioned readcommand processing can be executed in the same way for write commandprocessing.

According to this embodiment, the command controller 251 is able, alsoafter capacity expansion of the 3390-A format LDEV 322, to access anLDEV 322 according to 3390-A format data placement in the real storagearea as a 3390 format LDEV 322 by using an address obtained through theaddress conversion by the address conversion unit 254.

Embodiment 3

In this embodiment, a plurality of 3390-A format volumes, which arevolumes in the real storage area, are prepared, these volumes beingmanaged in the real storage area by placing distributed user data areasin one volume and distributed control information areas in the othervolume.

<System for Saving and Managing User Data Areas and Control InformationAreas in Different Volumes>

FIG. 22 shows an example in which the distributed user data area 1401and distributed control information area 1411 in the cylinder group 1421are saved and managed in different volumes.

In FIG. 22, the HDEV 2201 has the same configuration as the HDEV 321, aplurality (m) of tracks are placed in the HDEV 2201 and two LDEV 2202and 2203 are associated. The LDEV 2202 comprises a volume for storing aplurality (n) of distributed user data areas 1401 . . . , and the LDEV2203 comprises a volume for storing a plurality (n) of distributedcontrol information areas 1411 . . . .

Here, in cases where the cylinder group 1421 comprises a distributeduser data area 1401 and a distributed control information area 1411, thedistributed user data area 1401 is placed in the LDEV 2202 and thedistributed control information area 1411 is placed in the LDEV 2203different from the LDEV 2202. The LDEV 2202 therefore comprises a largecapacity and the LDEV 2203 comprises a small capacity and are compatiblewith volume capacity expansion.

Furthermore, for example, by combining the distributed user data area1401 saved in the LDEV 2202 with the distributed control informationarea 1411 corresponding to the distributed user data area 1401 saved inthe LDEV 2203, the foregoing areas may be regarded as one cylindergroup. Furthermore, when one or more cylinder groups, obtained bycombining each of the distributed user data areas of the LDEV 2202 andthe control information areas of the LDEV 2203 which correspond to eachof the distributed user data areas, are brought together, the cylindergroups may be regarded as a 3390-A format LDEV.

FIG. 23 shows a configuration of a management table 2300 for managingthe addresses of distributed user data areas and distributed controlinformation areas.

In FIG. 23, the management table 2300 comprises a distributed user dataarea number field 2301, an on-LDEV address field 2302, a distributedcontrol information area number field 2303, and an on-LDEV address field2304.

The entries of the distributed user data area number field 2301 eachstore the numbers of the distributed user data areas disposed in theLDEV 2202, and the entries of the on-LDEV address field 2302 each storethe addresses of the distributed user data areas disposed in the LDEV2202. The entries of the distributed control information area numberfield 2303 each store the numbers of the distributed control informationareas disposed in the LDEV 2203, and the entries of the on-LDEV addressfield 2304 each store the addresses of the distributed controlinformation areas disposed in the LDEV 2203.

Processing for a case where the MF host computer 102 performs readaccess to the HDEV 2201 will be explained next.

The parameters for read access by the MF host computer 102 are the HDEVnumber and the track number, and so on.

When the MF host computer 102 transmits a read command to the storagecontroller 131, the command controller 251 in the microprogram 231refers to the HDEV 2201 according to the parameters for the read commandfrom the MF host computer 102. Thereafter, the command controller 251 inthe microprogram 231 calculates the LDEV number, the address of the datapart 325 in the track on the 3390 format LDEV, and the address of thecontrol information part 326 based on the aforementioned HDEV number andtrack number, and informs the address conversion unit 254.

The address conversion unit 254 refers to the management table 1700 andthe management table 1800, acquires the sizes of the distributed userdata area and the distributed control information area and the startaddresses of the 3390-format distributed user data area and distributedcontrol information area, calculates the LDEV number in the 3390-Aformat LDEV and the track number based on the acquired information, theaddress of the in-track data part 325, and the address of the controlinformation part 326, and informs the command controller 251 of thisLDEV number and track number.

Upon receiving a read address from the MF host computer 102 via the hostI/F 121, the command controller 251 calculates, from the received tracknumber, the number of the distributed user data area in the 3390-Aformat LDEV and an offset address from the start address of thedistributed user data area to the data part 325 of the track number, thenumber of the distributed control information area in the 3390-A formatLDEV, and an offset address from the start address of the distributedcontrol information area to the control information part 326 of thetrack number.

The command controller 251 refers to the management table 2300 toacquire the address of the distributed user data area, and acquires anaddress indicating the data part 325 of the track number in thedistributed user data area in the LDEV 2202 based on the acquiredaddress, the number of the distributed user data area, and the offsetaddress.

Furthermore, the command controller 251 refers to the management table2300 to acquire the address of the distributed control information area,and acquires an address indicating the control information area 326 ofthe track number in the distributed control information area in the LDEV2203 based on the acquired address, the number of the distributedcontrol information area, and the offset address.

The command controller 251 subsequently performs access to the data part325 of the read, target track in the distributed user data area, basedon the acquired address.

Furthermore, the command controller 251 may refer to or update thecontrol information part 326 of the read target track in the distributedcontrol information area on the basis of the acquired address. Note thatif it is not necessary to refer to the control information part 326 ofthe read target track, the processing in which the command controller251 refers to the control information part 326 of the read target trackcan be omitted.

The command controller 251 transmits a data part 325 in the read targettrack to the MF host computer 102 via the host I/F 121.

An example of read access in a case where distributed user data areasand distributed control information areas are saved and managed indifferent volumes was provided hereinabove.

Note that access processing with respect to the track above can beexecuted in the same way also when the type of access by the MF hostcomputer 102 is write access.

In this embodiment, a plurality of 3390-A format volumes, which arevolumes in the real storage area, are prepared, these volumes beingmanaged in the real storage area by placing user data areas in onevolume and control information areas in the other volume. For thisreason, a volume (LDEV 2203) in which the distributed controlinformation areas are disposed can comprise a small capacity and avolume (LDEV 2202) in which the distributed user data areas are disposedcan comprise a large capacity. In this case, even when the LDEV 2203comprises a small capacity and the LDEV 2202 comprises a large capacity,these LDEV are compatible with volume capacity expansion.

Embodiment 4

In this embodiment, a data copy is made from the 3390 format LDEV 322 tothe 3390-A format LDEV 322.

<Data Copy Processing from the 3390 Format LDEV 322 to the 3390-A FormatLDEV 322>

Processing to copy the data part of the track from the 3390 format LDEV322 to the 3390-A format LDEV 322 will be explained next with referenceto the flowchart in FIG. 24.

First, the following is premised on the fact that the copy-source 3390format LDEV 322 is referenced by means of an address (s), the copydestination is the 3390-A format LDEV 322, and the 3390-A format LDEV322 comprises one or more cylinder groups 1421. Here, the data part 325of the track in the 3390-A format LDEV is accessed by means of a number(n) of the distributed user data area and an offset address (d) from thestart address of the nth distributed user data area.

Upon receiving a copy start instruction from the management hostcomputer 103 via the management host I/F 127, the command controller 251in the microprogram 231 starts copy processing.

The command controller 251 configures the start address of the copysource LDEV 322 as the copy source address (s) and sets the copy sourceaddress (s) at 0 (S41).

Thereafter, the command controller 251 determines whether or not thecopy source address (s) is the final address of the copy source LDEV 322(S42) and if the copy source address (s) points to the final address ofthe copy source LDEV 322, the command controller 251 informs themanagement host computer 103 that the copy processing is complete viathe management host I/F 127, and ends the copy processing.

However, if it is determined that the copy source address (s) is thefinal address of the copy source LDEV 322, the command controller 251informs the address conversion unit 254 of the copy source address (s).

The address conversion unit 254 subsequently refers to the managementtable 1700 to acquire the size of the distributed user data area andrefers to the management table 1800 to acquire the start addresses ofthe distributed user data area and distributed control information area,and, based on the acquired size, start address, and copy source address(s), calculates the number (n) of the distributed user data area, andthe value of the offset address (d) from the start address of thecopy-destination distributed user data area (n), and informs the commandcontroller 251 of the calculation result (S43).

The command controller 251 determines whether or not the distributeduser data area (n) is the final distributed user data area of the copydestination LDEV (S44), and if the distributed user data area (n) is thefinal distributed user data area of the copy destination LDEV, becausethe capacity of the copy source LDEV is greater than the capacity of thecopy destination LDEV 322, the command controller 251 informs themanagement host computer 103 that the copy has failed via the managementhost I/F 127, and ends the copy processing.

However, if it is determined that the distributed user data area (n) isnot a final distributed user data area of the copy destination LDEV, thecommand controller 251 copies the data (data part 325) from the storagearea indicated by the copy source address (s) to the storage areaindicated by the offset address (d) from the start address in thecopy-destination distributed user data area (n) (S45).

The command controller 251 subsequently increments the copy sourceaddress (s) (s=s+1), and returns to the processing of step S32 (S46).The processing of steps S32 to S36 is subsequently repeated until anaffirmative determination result is obtained in step S32.

By executing the processing of steps S41 to S46, the data part 325 inthe distributed user data area 1401 in the 3390 format storage area 910,for example, can be copied into the distributed user data area 1401 inthe 3390-A format real storage area 930.

Furthermore, processing to copy the control information part 326 of thetrack from the 3390 format LDEV 322 to the 3390-A format LDEV 322 canalso be executed in the same way. In this case, the control informationpart 326 in the distributed control information area 1411 in the 3390format storage area 910, for example, can be copied into the distributedcontrol information area 1411 in the 3390-A format real storage area930.

The volume of data copied may either be all of the data or some of thedata in the copy source LDEV 322.

In the data copy processing from the 3390 format LDEV 322 to the 3390-Aformat LDEV 322, the distributed control information areas may be copiedafter finishing the copying of the distributed user data areas, or inthe reverse order. In addition, some of the distributed controlinformation area may be copied after finishing the copying of some ofthe distributed user data areas, and then vice versa in alternatefashion.

In addition, processing to copy data from the 3390-A format LDEV 322 tothe 3390 format LDEV 322 and processing to change the address of the3390-A format LDEV 322 to the address of the 3390 format LDEV 322 canalso be executed in the same way.

According to this embodiment, by performing data copying from the 3390format LDEV 322 to the 3390-A format LDEV 322, the data part 325 and thecontrol information part 326 in the real storage area can be constructedfrom the data part 325 and the control information part 326 which belongto the 3390 format LDEV 322.

Embodiment 5

This embodiment is configured such that the LDEV 322 are managed asvirtual volumes which comprise virtual storage area and such that ifthere is access to a virtual volume, real storage area is allocated froma pool to the virtual volume.

<Processing Relating to Real Storage Area Allocation to the VirtualVolume>

Processing which relates to the allocation of real storage area to thevirtual volume includes the aforementioned address conversionprocessing, and page allocation processing which will be describedsubsequently. In the page allocation processing, the allocation of realstorage area to the virtual storage area in the event of a host write tothe virtual volume is performed on the basis of the page managementtable and page management directory. A function for performingprocessing which is related to the allocation of real storage area tothe virtual volume will be referred to hereinafter as Thin Provisioningfunction.

FIG. 25 shows the configuration of the page management table 2500 usedin the page allocation processing.

In FIG. 25, the page management table 2500 is a table which is used whenexecuting processing to allocate real storage area to virtual volumes,and which comprises a page number field 2501, an LDEV page start addressfield 2502, a disk number field 2503, a disk page start address field2504, and an allocated determination information field 2505, and thepage management table 2500 exists for each LDEV 322, being stored in themain memory 123 or cache memory 124, and so on.

Each entry of the page number field 2501 stores the page number of thepage allocated to the LDEV 322. Each entry of the LDEV page startaddress field 2502 stores the start address of a page allocated to theLDEV 322. Each entry of the disk number field 2503 stores the number ofa disk 132 which the LDEV 322 comprises.

The disk page start address is the start address of a real storage areain a disk and each entry of the disk page start address field 2504stores the start address of a disk 132 which the LDEV 322 comprises. Ifa page has been allocated to the LDEV 322, the information Allocated isstored in each entry of the allocated determination information field2505, and if a page has not been allocated to the LDEV 322, theinformation Unallocated is stored in each entry. That is, the allocateddetermination information is used to manage the state of allocation ofthe real storage area to the virtual storage area, taking the pages asunits.

A page is a storage area of a fixed size which is stored in the pool 323and is a unit for allocating and managing the storage area of the LDEV322. Furthermore, a page is a collection of one or more tracks, and soon. A track can be of a fixed size, for example 59392 bytes in thestorage apparatus 101.

FIG. 26 shows the configuration of a page management directory 2600which is used in page allocation processing.

In FIG. 26, the page management directory 2600 is a table for managingcorrespondence relationships between the LDEV 322 and page managementtables 2500, and which comprises an LDEV number field 2601 and theaddress field 2602 of the page management table, the page managementdirectory 2600 being saved in the main memory 123 or the cache memory124, or on a disk 132, and so on.

Each entry of the LDEV number field 2601 stores the number of an LDEV322. Each entry of the address field 2602 of the page management tablestores an address of a page management table 2500 for managing pages ofthe LDEV 322.

An example of processing when the command controller 251 receives writeaccess from the MF host computer 102 will be described next. Theparameters during write access are the LDEV number and the track numberin the LDEV, and so on.

If write access parameters are received from the MF host computer 102,the command controller 251 calculates the address in the LDEV 322 basedon the track number and track size of the LDEV 322.

The command controller 251 subsequently refers to the page managementdirectory 2600 and acquires the address of the page management table2500 corresponding to the LDEV number.

The command controller 251 subsequently refers to the page managementtable 2500 corresponding to the acquired address, searches for the pagecontaining the track indicated by the address in the write accessdestination, and acquires the page number obtained in the search and anoffset address from the page start address to the write accessdestination track.

Thereafter, the command controller 251 refers to the allocateddetermination information in the page entry of the acquired page number,and if the allocated determination information indicates an allocatedstate, the command controller 251 performs write access to the data part325 of the write access destination track number which is specified bythe page start address in the disk corresponding to the page entry.

If the allocated determination information is in an unallocated state,the command controller 251 refers to the management table 700 to acquirea pool number which corresponds to an LDEV number, refers to themanagement table 800 on the basis of the acquired pool number to acquirethe disk number corresponding to the pool number, and allocates the realstorage area in page units from one or more disks 132 which belong tothe pool 323 corresponding to the LDEV number 322 on the basis of theacquired disk number.

Here, the command controller 251 refers to the page management table2500, seeks the page entry which contains the track indicated by thewrite access destination address, registers the start address of thenewly allocated page in the page management table 2500, and updatesUnallocated in the allocated determination information field 2502 toAllocated, and updates the page management table 2500.

Processing for allocating pages from a pool to a virtual volume wasdescribed hereinabove.

<Page Allocation Processing if 3390-A Format LDEV 322 is Constructed ona Virtual Volume>

Processing will be described next with reference to the flowchart ofFIG. 27 and in which processing pages are allocated to each of the userdata areas and to each of the control information areas corresponding tothe user data areas, in the event of write access of the MF hostcomputers 102 in cases where a 3390-A format LDEV 322 is constructed ina virtual volume.

Processing when the command controller 251 receives write access fromthe MF host computer 102 via the MF host I/F 121 will be describedhereafter.

The parameters during write access are the LDEV number in the 3390format LDEV 322 and the track number in the LDEV, and so on.

First, upon starting the MF host write command processing, the commandcontroller 251 refers to the management table 500 of FIG. 5, acquiresthe volume capacity of the LDEV 322, and calculates the address of thedata part 325 of the track in the LDEV 322 corresponding to the tracknumber of the LDEV 322 and likewise the address of the controlinformation part 326 of the track, based on the acquired volume capacityand preset track size of the LDEV 322.

Thereafter, the command controller 251 refers to the management table1700 to acquire the sizes of the distributed user data and distributedcontrol information, refers to the management table 1800 to acquire thestart addresses of the distributed user data area and distributedcontrol information area, and calculates the address of the data part325 of the track in the 3390-A format LDEV (data address) and theaddress of the control information part 326 (control informationaddress) on the basis of the sizes of the acquired distributed user dataand distributed control information, the start addresses of thedistributed user data area and distributed control information area, andthe address of the data part 325 (the data address) and the address ofthe control information part 326 (the control information address) whichare obtained in this calculation (S51).

The command controller 251 subsequently refers to the page managementdirectory 2600 on the basis of the LDEV number and acquires the addressof the page management table 2500 corresponding to the LDEV number.

The command controller 251 refers to the page management table 2500which corresponds to the acquired address, and acquires each of the pagenumbers of the pages which contain the data indicated by the address(data address) and address (control information address) obtained inthis calculation.

The command controller 251 refers to the allocated determinationinformation in the page entry corresponding to the acquired page numberin the page management table 2500, determines whether or not the pagecontaining the address (data address) has been allocated real storagearea (S52), and if the allocated determination information indicates anallocated state, that is, if it is determined that real storage area hasbeen allocated, the command controller 251 advances to the processing ofstep S56.

On the other hand, if the allocated determination information is in anunallocated state, that is, if it is determined that the page containingthe address (data address) has not been allocated real storage area, thecommand controller 251 refers to the management table 700 to acquire apool number which corresponds to an LDEV number, refers to themanagement table 800 on the basis of the acquired pool number to acquirethe disk number corresponding to the pool number, and, on the basis ofthe acquired disk number, allocates real storage area in page units fromone or more disks 132 which belong to the pool 323 corresponding to theLDEV number 322 (S53). That is, page allocation to the page containingthe address (data address) is executed.

The command controller 251 subsequently determines whether or not thepage containing the address (control information address) has beenallocated real storage area (S54), and if the allocated determinationinformation indicates an allocated state, that is, if it is determinedthat real storage area has been allocated, the command controller 251advances to the processing of step S56.

If it is determined in step S54 that the page containing the address(control information address) has been allocated real storage area, thecommand controller 251 refers to the management table 700 to acquire apool number which corresponds to an LDEV number, refers to themanagement table 800 on the basis of the acquired pool number to acquirethe disk number corresponding to the pool number, and allocates the realstorage area in page units from one or more disks 132 which belong tothe pool 323 corresponding to the LDEV number 322 on the basis of theacquired disk number (S55), and advances to the processing of step S56.That is, in step S55, page allocation to the page containing the address(control information address) is executed.

In step S56, the command controller 251 generates control informationwhich corresponds to the data part 325 of the track in an area indicatedby the address (control information address).

If the page containing the address (data address) has been allocatedreal storage area, the command controller 251 writes data to the areaindicated by the address (data address). That is, the command controller251 performs write access to the data part 325 with the page writeaccess destination track number (S57).

Here, the command controller 251 refers to the page management table2500, seeks the page entry containing the track indicated by the addressin the write access destination, registers the newly allocated pagestart address to the page management table 2500, changes Unallocated inthe allocated determination information field 2502 to Allocated, updatesthe page management table 2500, and ends the processing of this routine.

The command controller 251 may perform write access after initializingthe control information area to which the address (control informationaddress) belongs in the aforementioned page allocation processing.

According to this embodiment, if the real storage area is allocated tothe virtual volume, the page of the data part 325 and the page of thecontrol information part 326 can be allocated from the pool.

Embodiment 6

This embodiment is configured such that if the copy target data istransmitted as the data according to the remote copy processing to thecopy destination storage controller from the copy source storagecontroller and if the copy destination storage controller receives thecopy target data, the copy destination storage controller determines theinformation relating to the existence of a record in the received copytarget data, and executes processing according to the determinationresult.

<0 Data Page Discard Processing in Sync with the Remote Copy Processingwhen the 3390-A Format LDEV 322 is Constructed on a Virtual Volume>

FIG. 28 is a flowchart showing processing, in the second storageapparatus, to render the page state in the reception LDEV 322Unallocated in sync with remote copy processing to transmit data fromthe first storage apparatus 101 to the 3390-A format LDEV 322 which issaved in the virtual volume.

Returning the page state to unallocated will be referred to as PageDiscarding hereafter.

Remote copy processing is executed in a first storage apparatus 101 anda second storage apparatus 101 as below.

If a first command controller 251 in the first storage apparatus 101receives a remote copy request from the management host 103 via themanagement host I/F 127 in the first storage apparatus 101, the firstcommand controller 251 takes, as copy target data, the data parts 325 ofsome or all the tracks of the first LDEV 322 (3390 format or 3390-Aformat) in the first storage apparatus 101, and the control informationparts 326 of some or all the tracks and reads this copy target data fromone or more disks 132 to a first cache memory 124.

The first command controller 251 transmits some or all the tracks of theLDEV 322 in the first cache memory in fixed data units via a first hostI/F 121 in the first storage apparatus 101 and the network 111. The dataunits may be data parts 325 of one or more tracks or control informationparts 326 of one or more tracks, and so on.

However, when a second command controller 251 in the second storageapparatus 101 receives copy target data from the first commandcontroller 251 via a second host I/F 121 in the second storagecontroller 101, the second command controller 251 starts copy datareception processing, and writes the received copy target data to asecond cache memory 124 in the second storage apparatus 101 (S61).

Here, the second LDEV 322 in the second storage apparatus 101 isconstructed, according to the 3390-A format, on a virtual volume whichis used by Thin Provisioning function.

The second command controller 251 determines, for each of the data parts325 in the copy target data saved to the second cache memory 124,whether or not the aforementioned record exists in the track (S62), andif it is determined that the data part 325 of the track in the cachememory 124 has no record, the second command controller 251 advances tothe processing of step S66, and if it is determined that there is arecord for the data part 325 of the track in the cache memory 124, thesecond command controller 251 advances to the processing of step S63.Here, the second command controller 251 saves the results of checkingwhether or not there is a record for each track, in the record existenceinformation part 327 corresponding to the data part 325 of each track inthe second LDEV 322.

In step S63, the second command controller 251 determines whether or notthe page containing the data part 325 or control information part 326has been allocated real storage area.

More specifically, the second command controller 251 refers to the pagemanagement table 2500 and the page management directory 2600 on thebasis of the LDEV number of the LDEV 322 and checks whether or not awrite destination page has been allocated from the pool 323 to the writedestination virtual area of the data part 325 and control informationpart 326 which belong to the copy target data, which is a writedestination virtual area in the second cache memory 124.

If it is determined that the page containing the data part 325 orcontrol information part 326 has not been allocated real storage area,the second command controller 251 allocates real storage area in thepool 323 to the page containing the data part 325 or control informationpart 326 (S64).

More specifically, if the write destination page of the data part 325 ofone or more tracks in the second cache memory 124 is in an unallocatedstate and there is a record in the data parts 325 of these tracks, thesecond command controller 251 refers to the management table 700 on thebasis of the LDEV number of the LDEV 322, acquires a pool number whichcorresponds to the LDEV number, refers to the management table 800 onthe basis of the acquired pool number, acquires a disk numbercorresponding to the pool number, and allocates the real storage area inpage units from one or more disks which belong to the pool 323corresponding to the LDEV number of the LDEV 322.

Likewise, if the write destination page of the control information part326 of one or more tracks in the second cache memory 124 is in anunallocated state, the second command controller 251 refers to themanagement table 700 on the basis of the LDEV number of the LDEV 322 toacquire a pool number which corresponds to the LDEV number, refers tothe management table 800 on the basis of the acquired pool number toacquire a disk number corresponding to the pool number, and, based onthe acquired disk number, allocates the real storage area in page unitsfrom one or more disks which belong to the pool corresponding to theLDEV number of the LDEV 322.

The second command controller 251 subsequently writes the data parts 325and the control information parts 326 in the second cache memory 124 tothe allocated real storage area (S65).

More specifically, if the write destination page of the data part 325which belongs to the copy target data is in a state of being allocatedto the write destination virtual area in the second cache memory 124,the second command controller 251 writes the data parts 325 which belongto the copy target data in the second cache memory 124 to one or moresecond disks 132 which form part of the real storage area in the pool323.

Similarly, if the write destination page of the control information part326 which belongs to the copy target data is in a state of beingallocated to the write destination virtual area in the second cachememory 124, the second command controller 251 writes the controlinformation parts 326 which belong to the copy target data in the secondcache memory 124 to one or more disks 132 which form part of the realstorage area in the pool 323.

The second command controller 251 subsequently seeks, based on the pagemanagement table 2500, the page entry which contains the data part 325of the track of the write access destination, registers the startaddress of the newly allocated page, and updates the allocateddetermination information to an allocated state. Likewise, the secondcommand controller 251 seeks, based on the page management table 2500,the page entry which contains the control information part 326 of thetrack of the write access destination, registers the start address ofthe newly allocated page, and updates the allocated determinationinformation to an allocated state.

The second command controller 251 subsequently writes the aforementioneddata parts 325 of one or more tracks to one or more second disks 132that form part of the real storage area in the pool 323, and writes thecontrol information parts 326 of the one or more tracks to one or moresecond disks 132 that form part of the real storage area in the pool323.

Thereafter, in step 66, the second command controller 251 savesinformation indicating that there is a record in the record existenceinformation parts 327 which correspond to the data parts 325 of the oneor more tracks of the second LDEV 322 and updates the record existenceinformation parts 327.

If the write destination page of the data parts of the one or moretracks in the second cache memory 124 is in an unallocated state and ifthere is no record in the data parts of these tracks, the second commandcontroller 251 does not allocate a page from the pool 323 to the writedestination virtual area of the second cache memory 124. In this case,the second command controller 251 does not write the data parts 325 ofthe one or more tracks to the one or more second disks 132. Furthermore,the second command controller 251 saves information indicating a statewhere there is no record in the record existence information parts 327which correspond to the data parts 325 of the tracks of the second LDEV322.

If the write destination page of the data parts of the one or moretracks in the second cache memory 124 is in an unallocated state and ifthere is no record in the data parts of these tracks, the second commandcontroller 251 may write an initial value indicating that there is norecord after allocating a page from the pool 323.

Furthermore, in step S66, the second command controller 251 checks forthe existence of a record of the data parts 325 in the tracks inallocated pages of the second LDEV 322, saves information indicatingthat there is no record in the record existence information parts 327 ofthe tracks where no record exists and updates the record existenceinformation parts 327.

The second command controller 251 then checks for the existence ofrecords in the data parts 325 of the tracks in allocated pages of thesecond LDEV 322 on the basis of the values of the record existenceinformation parts 327 of all the tracks in the second LDEV 322,implements a state where pages with no record are placed in anunallocated state, that is, executes page discarding (S67), and ends theprocessing of this routine.

In this embodiment, with the first storage controller 131 in the firststorage apparatus 101 serving as the other controller, the secondstorage controller 131 in the second storage apparatus exchangesinformation via the network 111 and the first storage controller 131,and determines whether or not information relating to recordscorresponding to tracks exist as information relating to first dataparts 325 or second data parts 325 among the information received fromthe first storage controller 131, stores the determination results inthe second control information area of the virtual volume (3390-A formatLDEV 322), and if the determination results stored in the second controlinformation area of the virtual volume indicate that a recordcorresponding to a track does not exist, executes processing to releasethe page allocated to the virtual volume from the pool as real storagearea corresponding to the track in the same way as in remote copyprocessing.

The aforementioned page discard processing may also be carried outbefore writing copy target data corresponding to one or more tracks, inthe second cache memory 124, to one or more disks 132 in the secondcache memory 124.

The foregoing is an example of processing in which remote data copyingis implemented with respect to a second LDEV 322 in the second storageapparatus 101 from a first LDEV 322 in the first storage apparatus 101.

According to this embodiment, upon receiving copy target data from thefirst storage controller 131 in the first storage apparatus 101, thesecond storage controller 131 in the second storage apparatus 101 isable to check for the existence of records of the data parts 325 of thetracks and place pages for which no record exists in an unallocatedstate, that is, execute page discard processing.

In this embodiment, in processing in which the first command controller251 reads copy target data, which includes data parts 325 of one or moretracks and control information parts 326 of one or more tracks, of atransmission-side first LDEV 322, from one or more disks 132 to thefirst cache memory 124, the first command controller 251 may refer torecord existence information parts 327 corresponding to data parts 325of one or more tracks in the first cache memory 124, and if there is norecord in data parts 325 which belong to the copy target data, the firstcommand controller 251 need not transmit the data parts 325 of thesetracks to the second storage apparatus. Furthermore, the first commandcontroller 251 may also inform the second storage apparatus, via amessage, that there is no record in the data parts 325 of these tracks.

If the MF host computer 102 performs processing in which the values ofthe control information parts 326 of the tracks are not recognized dueto a 3390-format LDEV 322, it is possible to skip over the controlinformation parts 326 of the tracks and thereby reduce the processingoverhead of aligning the disk head with the track data parts 325.

Embodiments of the present invention were described hereinabove but thepresent invention is not limited to these embodiments, rather it isunderstood that various modifications are possible within the spirit ofthe invention. For example, address conversion processing when expandingvolume capacity in cases where volume capacity has been reduced due tocylinder group removal or the like can also be applied to addressconversion processing when volume capacity is reduced.

REFERENCE SIGNS LIST

-   -   101 Storage apparatus    -   102 MF host computer    -   103 Management host computer    -   111, 113, 126 Network    -   122 CPU    -   123 Main memory    -   231 Microprogram    -   124 Cache memory    -   131 Storage controller    -   132 Disk    -   322 LDEV    -   323 Pool    -   325 Data part    -   326 Control information part    -   327 Record existence information part    -   901 Storage area    -   920, 930 Real storage area    -   1401 to 1405 Distributed user data area    -   1411 to 1415 Distributed control information area    -   1421 to 1425 Cylinder group (CG)    -   2202, 2203 LDEV

The invention claimed is:
 1. A storage apparatus, comprising: one ormore storage devices which store data; and a controller which managesone or more logical volumes constructed in storage areas of the storagedevices and which controls data input/output processing against thestorage devices on the basis of an access request from an access requestsource, wherein the controller: manages the logical volumes as firstlogical volumes in a first volume format, which includes a plurality offirst data areas storing one or more data parts including one or morerecords corresponding to tracks, and a plurality of first controlinformation areas storing one or more control information partsincluding control information for accessing each of the data partsstored in each of the first data areas, and the first volume format isof a first data placement in which the first data areas and the firstcontrol information areas are targets in which capacities are changed,and manages the logical volumes as second logical volumes in a secondvolume format, which includes a plurality of groups each of which isformed from a storage area, and which is of a second data placement inwhich each of the groups is a unit at which capacity is changed, and thestorage area is corresponding to a real storage area of the storagedevices, and including a second data area corresponding to the one firstdata area and a second control information area corresponding to the onefirst control information area, the second data area, which belongs tothe one of the plurality of groups, being located in the to of the oneof the plurality of groups, wherein, when an access request for accessto the data part belonging to any of the first data areas is received,the controller: calculates a first data address of the data partbelonging to the first data area as an access destination based on theaccess request, converts the calculated first data address into a seconddata address of a data part belonging to the second data area of any ofthe groups on the basis of the sizes of the second data area and thesecond control information area which belong to the one group, andexecutes data input/output processing against the second logical volumein accordance with the converted second data address.
 2. The storageapparatus according to claim 1, wherein the controller: specifies thedata part on the basis of a track number that is added to the accessrequest, calculates the first data address as the address of thespecified data part on the basis of the capacity of the logical volumeand the size of a track which corresponds to the track number, andconverts the calculated first data address into the second data addresson the basis of the sizes of the second data area and the second controlinformation area.
 3. The storage apparatus according to claim 1,wherein, if the capacity of the first logical volume is changed, thecontroller changes the number of the first data areas and the number ofthe first control information areas in the first logical volume, andchanges the number of the groups in the second logical volume inresponse to the change in the capacity of the first logical volume, andif an access request is received from the access request source foraccess to a data part belonging to a first data area newly secured, dueto the change in the capacity in the first logical volume, thecontroller calculates a first address of the data part belonging to thenewly secured first data area on the basis of the access request foraccess to the data part belonging to the newly secured first data area,converts the calculated first address into a second address of a datapart belonging to a second data area of a group that is newly secureddue to the change in the number of groups, and executes datainput/output processing against the data part of the second logicalvolume according to the converted second address.
 4. The storageapparatus according to claim 1, wherein, if the first logical volume isa plurality of first logical volumes, the controller places the firstdata area in one of the first logical volumes of the plurality of firstlogical volumes, and places the first control information area in theother of the first logical volumes of the plurality of first logicalvolumes.
 5. The storage apparatus according to claim 1, furthercomprising: a pool which stores a plurality of pages comprising a realstorage area of the storage devices; and a virtual volume in which thestorage area serving as the access target of the controller is a virtualstorage area and the data placement of the virtual storage area is thesecond volume format, wherein, when an access request for access to thevirtual volume is received from the access request source and a pagecontaining a data part designated by the access request has beenallocated to the virtual volume from the pool, the controller accessesthe page allocated to the virtual volume, and wherein, when the pagecontaining the data part designated by the access request has not beenallocated to the virtual volume from the pool, the controller allocates,to the virtual volume, a first page containing a second data part of thesecond data area constructed in the second volume format from among theplurality of pages stored in the pool, and a second page containing asecond control information part of the second control information area,so that the controller accesses at least the first page among the pagesallocated to the virtual volume.
 6. The storage apparatus according toclaim 1, further comprising: a pool which stores a plurality of pagescomprising a real storage area of the storage devices; and a virtualvolume in which the storage area serving as the access target of thecontroller is a virtual storage area and the data placement of thevirtual storage area is the second volume format, wherein thecontroller: exchanges information with another controller via a network,determines whether or not information relating to the recordcorresponding to the track exists as information relating to the firstdata part or the second data part in the information received from theother controller, and stores the determined result in the second controlinformation area of the virtual volume.
 7. The storage apparatusaccording to claim 6, wherein, if the determined result stored in thesecond control information area of the virtual volume indicates that arecord corresponding to the track does not exist, the controllerreleases a page allocated to the virtual volume from the pool as a realstorage area which corresponds to the track.
 8. A storage apparatus,comprising: one or more storage devices which store data; and acontroller which manages one or more logical volumes constructed instorage areas of the storage devices and which controls datainput/output processing against the storage devices on the basis of anaccess request from an access request source, wherein the controller:manages the logical volumes as first logical volumes in a first volumeformat, which includes a plurality of first data areas storing one ormore data parts including one or more records corresponding to tracks,and a plurality of first control information areas storing one or morecontrol information parts including control information for accessingeach of the data parts stored in each of the first data areas, and thefirst volume format is of a first data placement in which the first dataareas and the first control information areas are targets in whichcapacities are changed, and manages the logical volumes as secondlogical volumes in a second volume format, which includes a plurality ofgroups each of which is formed from a storage area, and which is of asecond data placement in which each of the groups is a unit at whichcapacity is changed, and the storage area is corresponding to a realstorage area of the storage devices, and including a second data areacorresponding to the one first data area and a second controlinformation area corresponding to the one first control informationarea, wherein, when an access request for access to the data partbelonging to any of the first data areas is received, the controller:calculates a first data address of the data part belonging to the firstdata area as an access destination based on the access request, convertsthe calculated first data address into a second data address of a datapart belonging to the second data area of any of the groups on the basisof the sizes of the second data area and the second control informationarea which belong to the one group, and executes data input/outputprocessing against the second logical volume in accordance with theconverted second data address; wherein, if the first logical volume istaken as the copy source, the second logical volume is taken as the copydestination, and the data part and the control information part whichbelong to the first logical volume are copied to the second logicalvolume, the controller calculates the first data address and the firstcontrol information address as the copy source addresses of a first datapart and a first control information part which are a copy target amongthe first data parts and first control information parts belonging tothe first logical volume on the basis of information specifying the copytarget, calculates the second data address and the second controlinformation address as the copy destination addresses which indicate asecond data part belonging to the second data area and the secondcontrol information part belonging to the second control informationarea of any of the groups of the second logical volume, copies the firstdata part corresponding to the calculated first data address to thesecond data area corresponding to the calculated second data address,and copies the first control information part corresponding to thecalculated first control information address to the second controlinformation area corresponding to the calculated second controlinformation address.
 9. The storage apparatus according to claim 8,wherein, in the copy processing from the copy source to the copydestination, the controller executes a copy of the first controlinformation part of the copy target after the copy of the first datapart of the copy target has ended.
 10. The storage apparatus accordingto claim 8, wherein, in the copy processing from the copy source to thecopy destination, the controller alternately executes a partial copy ofthe first data part of the copy target and a partial copy of the firstcontrol information part of the copy target.
 11. A control method for astorage apparatus which comprises one or more storage devices storedata, and a controller which manages one or more logical volumesconstructed in storage areas of the storage devices and which controlsdata input/output processing against the storage devices on the basis ofan access request from an access request source, wherein the controller:manages the logical volumes as first logical volumes in a first volumeformat, which includes a plurality of first data areas storing one ormore data parts including one or more records corresponding to tracks,and a plurality of first control information areas storing one or morecontrol information parts including control information for accessingeach of the data parts stored in each of the first data areas, and thefirst volume format is of a first data placement in which the first dataareas and the first control information areas are targets in whichcapacities are changed, and manages the logical volumes as secondlogical volumes in a second volume format, which includes a plurality ofgroups each of which is formed from a storage area, with a second dataplacement in which each of the groups is a unit at which capacity ischanged, and the storage area is corresponding to a real storage area ofthe storage devices and including a second data area corresponding tothe one first data area and a second control information areacorresponding to the one first control information area, the second dataarea, which belongs to the one of the plurality of groups, being locatedin the to of the one of the plurality of groups, wherein, when an accessrequest for access to a data part belonging to any of the first dataareas is received, the controller: calculates a first data address ofthe data part belonging to the first data area as an access destinationbased on the access request, converts the calculated first data addressinto a second data address of a data part belonging to the second dataarea of any of the groups on the basis of the sizes of the second dataarea and the second control information area which belong to the onegroup, and executes data input/output processing against the secondlogical volume in accordance with the converted second data address. 12.The control method for a storage apparatus according to claim 11,wherein the controller: specifies the data part on the basis of a tracknumber that is added to the access request, calculates the first dataaddress as the address of the specified data part on the basis of thecapacity of the logical volume and the size of a track which correspondsto the track number, and converts the calculated first data address intothe second data address on the basis of the sizes of the second dataarea and the second control information area.
 13. The control method fora storage apparatus according to claim 11, wherein the controller:changes the number of the first data areas and the number of the firstcontrol information areas in the first logical volume when the capacityof the first logical volume is changed, and changes the number of thegroups in the second logical volume in response to the change in thecapacity of the first logical volume, and if an access request isreceived from the access request source for access to a data partbelonging to a first data area newly secured, due to the change incapacity, in the first logical volume, the controller: calculates afirst address of the data part belonging to the newly secured first dataarea on the basis of the access request for access to the data partbelonging to the newly secured first data area, converts the calculatedfirst address into a second address of a data part belonging to thesecond data area of the newly secured group in response to a change inthe number of groups, and executes data input/output processing againstthe data part of the second logical volume in accordance with theconverted second address.
 14. The control method for a storage apparatusaccording to claim 11, wherein, if the first logical volume is taken asthe copy source and the second logical volume is taken as the copydestination, and the data part and the control information part whichbelong to the first logical volume are copied to the second logicalvolume, the controller: calculates the first data address and the firstcontrol information address as the copy source addresses of a first datapart and a first control information part which are a copy target amongthe first data parts and first control information parts belonging tothe first logical volume on the basis of information specifying the copytarget, calculates the second data address and the second controlinformation address as the copy destination addresses which indicate asecond data part belonging to the second data area and a second controlinformation part belonging to the second control information area of anyof the groups of the second logical volume, copies the first data partcorresponding to the calculated first data address to the second dataarea corresponding to the calculated second data address, and copies thefirst control information part corresponding to the calculated firstcontrol information address to the second control information areacorresponding to the calculated second control information address. 15.The control method for a storage apparatus according to claim 11,further comprising: a pool which stores a plurality of pages comprisinga real storage area of the storage devices; and a virtual volume inwhich the storage area serving as the access target of the controller isa virtual storage area and the data placement of the virtual storagearea is the second volume format, wherein, when an access request foraccess to the virtual volume is received from the access request sourceand a page containing a data part designated by the access request hasbeen allocated to the virtual volume from the pool, the controlleraccesses the page allocated to the virtual volume, and wherein, when thepage containing the data part designated by the access request has notbeen allocated to the virtual volume from the pool, the controllerallocates, to the virtual volume, a first page containing a second datapart of the second data area constructed in the second volume formatfrom among the plurality of pages stored in the pool, and a second pagecontaining a second control information part of the second controlinformation area, so that the controller accesses at least the firstpage among the pages allocated to the virtual volume.